It is known from practice, depending on the location of a subscriber—or at any rate on an apparatus bearing a subscriber identification—within a cellular network for mobile telephony to invoice several rates to the subscriber.
In order to better compete, e.g., in situations where the subscriber is located close to home or to his job, and therefore may relatively simply dispose of a connection by way of the nonmobile telephone network, against links by way of said nonmobile telephone network, some providers of mobile telephony invoice a reduced rate for conversations in the home zone. For conversations from locations outside said zone, on the contrary, the customary mobile rate is invoiced.
In practice, the zone in which a discount is offered is determined by the cell (the base transceiver) which best covers the location of the home base of the subscriber in question. Said cell constitutes the access point by way of which the subscriber, when making a link, gains access to the telecommunications network.
This way of determining the subscriber's zone, however, leads to several objections.
To start with, the access point must be determined in advance, e.g., by determining, at the home or office location of the subscriber, with which cell there is made a link, which is very laborious. Determination by way of plan views or maps which indicate the range of various cells is unreliable, since the transmission ranges, particularly in urban and hilly surroundings, may have craggy and surprising contours.
Secondly, it is of special importance to the subscriber that it be known whether at specific positions, where he wants to call often, there may be called at the reduced rate. After all, the subscriber will like to ascertain whether, from a location from which there is called frequently, there is not structurally called at the high rate. Said communication of the rate or the cell used requires additional provisions and complicates the use of the network.
Thirdly, in this method of determining the zones in which a different rate is computed, it is laborious that in the event of the home zone or the office zone being changed, it must be determined anew what is the new access point determining the zone in question. In addition, subsequent to the change, rates must then be calculated otherwise in a first part of a period than in a second part of said period.
Fourthly, through reconfiguration of the network, e.g., by adding a base station, the zone in which the home locations or office locations of a large number of subscribers are located, may change as well, which, in a considerable area, once again requires the redetermination of the access points associated with subscribers which determine the zone in question, in order to guarantee that no great number of subscribers at, e.g., the home location or the office location, remains deprived of a reduced rate.
Fifthly, under the influence of, e.g., weather conditions, the demand for links, the side of a building where the subscriber is located, and the position in which a telephone set is held, at or already close to the exact home location or office location, there may be made contact with another cell than the one which, at the initial determination, was determined as a serving cell and therefore as a special access point. As a result, the reduced rate cannot be offered to many subscribers in a reliable manner.